Optical waveguide lateral alignment arrangement

Abstract

An arrangement for providing optical coupling between a pair of substrates is disclosed. The arrangement is capable of providing automatic alignment in the lateral direction, that is, the direction perpendicular to the direction of optical signal flow along the surface of the optical substrate. In accordance with the teachings of the present invention, an interlocking system of alignment grooves and alignment ridges are utilized to prevent this unwanted motion and aid in alignment between the two pieces. In particular, an alignment ridge, or ridges, are formed on the top surface of a first substrate and are disposed to be parallel with a plurality of optical waveguides formed in the first substrate. The corresponding alignment grooves are formed in the second substrate, where this substrate may contain a plurality of fibers held in associated v-grooves. Waveguide-to-waveguide communication is achieved by forming alignment ridges on a pair of waveguide containing substrates. The substrates may then be placed end-to-end, where the alignment grooves in the second substrate will interlock with both sets of alignment ridges. As long as the dimensions of the alignment ridges and grooves are formed to complement each other in size - and are spaced similarly in their respective substrates - the alignment ridges and grooves will interlock when the two substrates are joined, thus preventing motion between the two substrates in the lateral direction.

What is claimed is: 
     
       1. An optical communication system which provides optical communication between separate optical substrates, said system comprising a first substrate (10) containing at least one optical waveguide longitudinally disposed along a top surface thereof and at least one alignment ridge comprising a predetermined height and width disposed along said top surface parallel with said at least one optical waveguide and separated from said at least one optical waveguide by a predetermined distance; and   a second substrate (14) containing at least one alignment groove comprising a predetermined depth and width corresponding to said predetermined height and width of said at least one alignment ridge, said at least one alignment groove longitudinally disposed on a top surface of said second substrate, wherein said at least one alignment groove and said at least one alignment ridge are capable of interlocking when said first substrate and said second substrate are mated together to automatically align said first and said second substrates.   
     
     
       2. An optical communication system as defined in claim 1 wherein the first substrate contains a plurality of longitudinally disposed waveguides. 
     
     
       3. An optical communication system as defined in claim 1 wherein the first substrate contains a plurality of longitudinally disposed alignment ridges and the second substrate contains a plurality of longitudinally disposed alignment grooves which are capable of interlocking with said plurality of alignment ridges. 
     
     
       4. An optical communication system as defined in claim 1 for providing single mode optical communication between the first substrate and the second substrate. 
     
     
       5. An optical communication system as defined in claim 1 for providing multimode optical communication between the first substrate and the second substrate. 
     
     
       6. An optical communication system as defined in claim 1 wherein the the second substrate further comprises at least one longitudinal fiber groove of a predetermined depth and width for containing at least one optical fiber. 
     
     
       7. An optical communication system as defined in claim 6 wherein the second substrate contains a plurality of longitudinal fiber grooves for holding an array of optical fibers. 
     
     
       8. An optical communication system as defined in claim 6 wherein the at least one alignment groove is identical in width and depth to the at least one longitudinal fiber groove. 
     
     
       9. An optical communication system as defined in claim 6 wherein the at least one alignment groove comprises a width which corresponds to the predetermined width of the associated at least one alignment ridge and is different from the width of the at least one longitudinal fiber groove. 
     
     
       10. An optical communication system as defined in claim 1 wherein said optical communication system further comprises a third substrate (100) containing at least one optical waveguide longitudinally disposed along a top surface thereof in a manner which provides a path for optical communication with the at least one waveguide of the first optical substrate when said first and third substrates are mated end to end, and at least one alignment ridge comprising a predetermined height and width disposed along said top surface parallel with said at least one optical waveguide and separated from said at least one optical waveguide by the predetermined distance, said at least one alignment ridge of said third substrate capable of interlocking with the at least one alignment groove of the second substrate such that direct optical communication occurs between said first and third substrates when said first and third substrates are placed in direct end-to-end contact and interlocked with said second substrate.   
     
     
       11. An optical communication system as defined in claim 10 wherein the first substrate contains a plurality of waveguides; and   the third substrate contains a plurality of waveguides.   
     
     
       12. An optical communication system as defined in claims 10 wherein the first substrate contains a plurality of alignment ridges; and   the third substrate contains a plurality of alignment ridges.